From the back cover:
Dungeon delving can be delightful. Wandering in the wilderness is a wonderful way to pass the time. But for the ultimate in opportunity, intrigue, and unexpected danger, try visiting the nearest village, town, or city.
A city is much more than a rest stop, a watering hole, or a place to buy equipment. Any community, from the smallest hamlet to the most crowded medieval metropolis, offers adventuring possibilities that can't be found in any other environment. Cities of Mystery describes for the Dungeon Master how to create realistic, exciting, and vibrant communities—and gives him the tools to make his creations come alive.
Inside this folder are 12 different street layout patterns that can be combined in a multitude of ways, plus 33 buildings of various shapes and sizes that can be cut out and assembled. The components, scaled for use with 25mm miniature figures, allow you to create three-dimensional city scenes for characters to explore. Also included is a 64-page book that takes you step by step through the process of defining and designing the villages, towns, and cities of your campaign world. The book contains five adventure scenarios that make use of the street layouts and fold-up buildings—ideas designed to get you started on the way to making your cities come alive.